POLLY BOLIAN."The Hidden Staircase." Original cover and frontispiece illustration for the book of the same name, by Carolyn Keene, published as "A Nancy Drew Mystery Story." (New York: Cameo Series, Grosset & Dunlap, 1960). Gouache on board. 390x273 mm; 15 1/4x10 3/4 inches, on 18 1/2x12 3/4 inch-board. Unsigned. Cornered to matte and framed. A copy of the book accompanies the lot.